To a certain extent, the history of New York theater in the last decade has been the history of gay theater. Terrence McNally's Love! Valour! Compassion! which has made the journey from Manhattan Theater Club to the Walter Kerr with all its virtues intact, is a key moment in that history.

Unlike many recent gay plays, whose tone was accusatory and shrill, Love is not a political statement. It documents the moment when the word "gay," which used to mean merry and mirthful as well as "homosexual," has come to mean bittersweet, if not sorrowful.

The play, about eight men—lovers, former lovers, would-be lovers—spending three holiday weekends together over a summer in an old house in Duchess County, is full of...